﻿
using Microsoft.Extensions.Caching.Memory;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.Caching;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace Yuebon.Commons.Cache
{
    /// <summary>
    /// MemoryCache缓存操作
    /// </summary>
    public class MemoryCacheService : ICacheService
    {
        /// <summary>
        /// 
        /// </summary>
        private readonly IMemoryCache _cache = new Microsoft.Extensions.Caching.Memory.MemoryCache(new MemoryCacheOptions());

        ///// <summary>
        ///// 
        ///// </summary>
        ///// <param name="cache"></param>
        ////public MemoryCacheService(IMemoryCache cache)
        ////{
        ////    _cache = cache;

        ////}

        #region 验证缓存项是否存在
        /// <summary>
        /// 验证缓存项是否存在,TryGetValue 来检测 Key是否存在的
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public bool Exists(string key)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            object cached;
            return _cache.TryGetValue(key, out cached);
        }
        #endregion

        #region 添加缓存

        /// <summary>
        /// 添加缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">缓存Value</param>
        /// <returns></returns>
        public bool Add(string key, object value)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }
            _cache.Set(key, value);
            return Exists(key);
        }
        /// <summary>
        /// 添加缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">缓存Value</param>
        /// <param name="expiresSliding">滑动过期时长（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <param name="expiressAbsoulte">绝对过期时长</param>
        /// <returns></returns>
        public bool Add(string key, object value, TimeSpan expiresSliding, TimeSpan expiressAbsoulte)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }
            _cache.Set(key, value,
                    new MemoryCacheEntryOptions()
                    .SetSlidingExpiration(expiresSliding)
                    .SetAbsoluteExpiration(expiressAbsoulte)
                    );

            return Exists(key);
        }
        /// <summary>
        /// 添加缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">缓存Value</param>
        /// <param name="expiresIn">缓存时长</param>
        /// <param name="isSliding">是否滑动过期（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <returns></returns>
        public bool Add(string key, object value, TimeSpan expiresIn, bool isSliding = false)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }
            if (isSliding)
                _cache.Set(key, value,
                    new MemoryCacheEntryOptions()
                    .SetSlidingExpiration(expiresIn)
                    );
            else
                _cache.Set(key, value,
                new MemoryCacheEntryOptions()
                .SetAbsoluteExpiration(expiresIn)
                );

            return Exists(key);
        }


        /// <summary>
        /// 用键和值将某个缓存项插入缓存中，并指定基于时间的过期详细信息
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="obj">缓存Value</param>
        /// <param name="seconds">缓存时长</param>
        public  bool Add(string key, object obj, int seconds = 7200)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            if (obj == null)
            {
                throw new ArgumentNullException(nameof(obj));
            }
            var cache = System.Runtime.Caching.MemoryCache.Default;

            var policy = new CacheItemPolicy
            {
                AbsoluteExpiration = DateTime.Now.AddSeconds(seconds)
            };

            cache.Set(key, obj, policy);
            return Exists(key);
        }
        #endregion

        #region 删除缓存

        /// <summary>
        /// 删除缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public bool Remove(string key)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            _cache.Remove(key);

            return !Exists(key);
        }
        /// <summary>
        /// 批量删除缓存
        /// </summary>
        /// <param name="keys">缓存Key集合</param>
        /// <returns></returns>
        public void RemoveAll(IEnumerable<string> keys)
        {
            if (keys == null)
            {
                throw new ArgumentNullException(nameof(keys));
            }

            keys.ToList().ForEach(item => _cache.Remove(item));
        }

        /// <summary>
        /// 删除所有缓存
        /// </summary>
        public void RemoveCacheAll()
        {
            var l = GetCacheKeys();
            foreach (var s in l)
            {
                Remove(s);
            }
        }

        /// <summary>
        /// 删除匹配到的缓存
        /// </summary>
        /// <param name="pattern"></param>
        /// <returns></returns>
        public void RemoveByPattern(string pattern)
        {
            IList<string> l = SearchCacheRegex(pattern);
            foreach (var s in l)
            {
                Remove(s);
            }
        }

        /// <summary>
        /// 搜索 匹配到的缓存
        ///</summary>
        /// <param name="pattern"></param>
        /// <returns></returns>
        public IList<string> SearchCacheRegex(string pattern)
        {
            var cacheKeys = GetCacheKeys();
            var l = cacheKeys.Where(k => Regex.IsMatch(k, pattern)).ToList();
            return l.AsReadOnly();
        }

        #endregion

        #region 获取缓存
        /// <summary>
        /// 获取缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public T Get<T>(string key) where T : class
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            return _cache.Get(key) as T;
        }
        /// <summary>
        /// 获取缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <returns></returns>
        public object Get(string key)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            return _cache.Get(key);
        }
        /// <summary>
        /// 获取缓存集合
        /// </summary>
        /// <param name="keys">缓存Key集合</param>
        /// <returns></returns>
        public IDictionary<string, object> GetAll(IEnumerable<string> keys)
        {
            if (keys == null)
            {
                throw new ArgumentNullException(nameof(keys));
            }

            var dict = new Dictionary<string, object>();

            keys.ToList().ForEach(item => dict.Add(item, _cache.Get(item)));

            return dict;
        }


        /// <summary>
        /// 获取所有缓存键
        /// </summary>
        /// <returns></returns>
        public List<string> GetCacheKeys()
        {
            const BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
            var entries = _cache.GetType().GetField("_entries", flags).GetValue(_cache);
            var cacheItems = entries as IDictionary;
            var keys = new List<string>();
            if (cacheItems == null) return keys;
            foreach (DictionaryEntry cacheItem in cacheItems)
            {
                keys.Add(cacheItem.Key.ToString());
            }
            return keys;
        }
        #endregion

        #region 修改缓存
        /// <summary>
        /// 修改缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">新的缓存Value</param>
        /// <returns></returns>
        public bool Replace(string key, object value)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }
            if (Exists(key))
                if (!Remove(key)) return false;

            return Add(key, value);

        }
        /// <summary>
        /// 修改缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">新的缓存Value</param>
        /// <param name="expiresSliding">滑动过期时长（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <param name="expiressAbsoulte">绝对过期时长</param>
        /// <returns></returns>
        public bool Replace(string key, object value, TimeSpan expiresSliding, TimeSpan expiressAbsoulte)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }
            if (Exists(key))
                if (!Remove(key)) return false;

            return Add(key, value, expiresSliding, expiressAbsoulte);
        }
        /// <summary>
        /// 修改缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">新的缓存Value</param>
        /// <param name="expiresIn">缓存时长</param>
        /// <param name="isSliding">是否滑动过期（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <returns></returns>
        public bool Replace(string key, object value, TimeSpan expiresIn, bool isSliding = false)
        {
            if (key == null)
            {
                throw new ArgumentNullException(nameof(key));
            }
            if (value == null)
            {
                throw new ArgumentNullException(nameof(value));
            }
            if (Exists(key))
                if (!Remove(key)) return false;

            return Add(key, value, expiresIn, isSliding);
        }
        #endregion

        /// <summary>
        /// 
        /// </summary>
        public void Dispose()
        {
            if (_cache != null)
                _cache.Dispose();
            GC.SuppressFinalize(this);
        }
    }
}
